Four Egyptian policemen were killed and three others injured when an improvised explosive device went off on Monday near a security convoy in Sinai Peninsula, security and medical sources said.

The attack near Arish, the capital of North Sinai province, which is gripped by an insurgency, wounded three others, including a brigadier general who lost his leg, and destroyed three armoured vehicles. It also destroyed a signal-jamming vehicle.

There was no immediate claim of responsibility. Islamic State militants have been waging an insurgency in the area that has gained pace since the military toppled President Mohamed Mursi of the Muslim Brotherhood, Egypt’s oldest Islamist movement, following mass protests against his rule in mid-2013.

Hundreds of soldiers and policemen have been killed since.

There was no immediate comment from the Interior Ministry on Monday’s attack. State news agency MENA quoted a high ranking ministry official confirming the attack and casualty figures.

Security forces were exchanging fire with militants near the explosion site and managed to kill several of them, MENA said.